Industrial Hot Water Boiler Design

Industrial boiler systems can cope with much higher pressures than pressure cookers. These boilers are welded from thick steel plates that are up to 35 mm thick, making pressures of 30 bar and more possible. A stable, robust design is also essential – if a boiler of this type were to collapse, explosive forces comparable to the explosive power of a ton of gelignite would be released (milk boiling over in a pressure cooker is nothing in comparison to this). A thermal output of up to 38 MW is possible from a single boiler, which corresponds approximately to the power of 500 average VW cars. Up to boilers can be combined economically. A boiler of this type, filled with water and ready for function, can weigh as much as 165 tons, which corresponds to the weight of 120 VW Golfs

At full capacity a boiler of this size converts 3 000 litres of fuel oil or a corresponding amount of natural gas to thermal or process heat every hour. This would be sufficient to heat more than 2 000 houses.

Hot water or steam boilers are relatively similar in design. The boiler pressure vessel is a horizontal, cylindrical tube closed at both sides with an end plate and insulated all around. There is a flame tube (1st pass) in this pressure vessel, which is fired through a burner and an internally situated reversing chamber that reverses the flue gases and leads them back in the 2nd smoke tube pass. On the front of the boiler is an external reversing chamber, which again reverses the flue gases and leads them to the end of the boiler in the 3rd smoke tube pass. Hot water boilers are normally completely filled with water during operation. Steam boilers on the other hand are only 3/4 filled with water; the upper quarter is the steam space.

Because of the huge volume of water and the multi-stage lead-through of the flue gases, these boilers are also called three-pass shell boilers.

Three pass gas steam boiler supplier:...